In recent years, sanitary washing apparatuses (perineum washing apparatuses) in which flush water is jetted toward a user's perineum to wash the perineum have become widespread. Such a sanitary washing apparatus must be connected to water supply plumbing to supply wash water for jetting, and to electrical wiring for supplying electrical power to drive a wash water jetting nozzle. Because the sanitary washing apparatus is mounted on the top surface of the flush toilet main body, interference by plumbing and wiring with the flush toilet main body is generally avoided by connecting water supply pipes and electrical wiring on the side surface of the sanitary washing apparatus. However, when water supply pipes and electrical wiring are connected to the side surface of a sanitary washing apparatus, the pipes and wiring are exposed on the outside of the flush toilet main body, thereby detracting from the external appearance of the flush toilet apparatus as a whole. Also, effort is required to remove dust accumulating on exposed wiring and plumbing, and cleanability of the flush toilet apparatus as a whole is degraded.
Japanese Published Unexamined Patent Application JP2014189999 (Patent Document 1) sets forth a sanitary washing apparatus and toilet apparatus. In this sanitary washing apparatus, supply plumbing for supplying wash water is made to project rearward from the sanitary washing apparatus, and plumbing projecting rearward is bent further downward to pass through an opening formed on the top surface of the flush toilet main body. Using this sanitary washing apparatus, supply piping does not project to the side of the flush toilet, and thus can be easily hidden.
European Patent Application Publication EP2778302A2 (Patent Document 2) sets forth a wall-mounted toilet. In this wall-mounted toilet, an accessory hole for admitting electrical cords and supply plumbing is formed on the top surface of the flush toilet.